Microsoft KB Archive/248993

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Article ID: 248993

Article Last Modified on 3/1/2007


  • Microsoft Windows 2000 Server
  • Microsoft Windows 2000 Advanced Server
  • Microsoft Windows 2000 Professional Edition

This article was previously published under Q248993

IMPORTANT: This article contains information about modifying the registry. Before you modify the registry, make sure to back it up and make sure that you understand how to restore the registry if a problem occurs. For information about how to back up, restore, and edit the registry, click the following article number to view the article in the Microsoft Knowledge Base:

256986 Description of the Microsoft Windows Registry


When using the Performance Monitor tool (or System Monitor Microsoft Management Console [MMC] snap-in) a performance object may unexpectedly fail to appear in the Performance Object drop-down list box in the Add To Chart dialog box.


The problem may occur because the extensible performance DLL is marked as "disabled".


The object may be reenabled by setting the "Disable Performance Counters" registry value in the Performance subkey of the supported service for the extension.


This behavior is by design.


In versions of Windows NT prior to Windows 2000, one bad or defective performance DLL is able to render the performance monitoring features of the operating system inoperative. To maintain the integrity of the performance data and to improve reliability, the performance library of Windows 2000 disables any performance DLL that returns data in the incorrect format, causes an unhandled program fault, or takes too long to return the performance data (this is usually the cause of a library being disabled).

When a performance extension DLL is disabled, the performance counters provided by that DLL are not available through Performance Monitor or the Performance Data Helper API. Disabled DLLs are not reloaded when the system is restarted.

If a performance extension DLL becomes disabled unexpectedly, check the application event log for event 1017 or 1018 (the "disable" events) posted by the Perflib source. Then look for other events posted by Perflib that will give the reasons why the system disabled the extension. These events should be noted if you need to call technical support.

You can try reenabling the extension DLL. If the problem persists (that is, the system disables it again) you should contact the vendor of the extension. If the object is a Windows 2000 system object (such as the Process object) contact Microsoft Product Support Services (PSS).

To reenable an extension DLL, Microsoft recommends that you use the ExCtrlList utility from the Windows 2000 Resource Kit. Alternatively, you can use the Registry editor tool (Regedit.exe) that ships with Windows 2000.

Reenabling an Extension by Using ExCtrlLst

  1. Start Exctrlst.exe. This is a tool from the Windows 2000 Resource Kit.
  2. Select the first item in the Extensible Performance Counters list box.
  3. Inspect the Performance Counters Enabled checkbox that appears just below the list box. If the checkbox is selected, the counter is enabled. If it is cleared, then select the checkbox to reenable it.
  4. Select the next item in the Extensible Performance Counters list box and repeat the previous two steps until all items have the Performance Counters Enabled checkbox selected.

Reenabling an Extension by Using Regedit.exe

WARNING: If you use Registry Editor incorrectly, you may cause serious problems that may require you to reinstall your operating system. Microsoft cannot guarantee that you can solve problems that result from using Registry Editor incorrectly. Use Registry Editor at your own risk.

  1. Start Regedit.exe. (You cannot use Regedt32.exe because it does not allow searching for registry values.)
  2. Click to select the following key


  3. Select Find from the Edit menu.
  4. In the Find What field, type Disable Performance Counters.
  5. Click Find Next. This will locate a Performance key that may have this Registry value set to 1.
  6. If the Registry value is set to 1, set the value to 0 or delete the Registry value.
  7. Press F3 to find the next occurrence of this Registry value.
  8. Repeat the previous two steps until there are no Performance keys that have the Disable Performance Counters value set to 1.

NOTE: Often the "Disable Performance Counters" value does not appear in the registry. The value can be created and given a DWORD value of 1 to disable counters.

Additional query words: perfmon missing

Keywords: kbkernbase kbperfmon kbprb KB248993